Limit Testing
TDS 620A, 640A & 644A User Manual
3Ć73
H If you want to send a hardcopy command when waveform data
exceeds the limits set, toggle Hardcopy if Condition Met (side) to
ON. You can set the hardcopy system to send the hardcopy to the
file system (optional on the TDS 620A & TDS 640A). (Do not forget
to set up the hardcopy system. See Hardcopy on page 3Ć57 for
details.)
H If you want the bell to ring when waveform data exceeds the limits
set, toggle Ring Bell if Condition Met (side) to ON.
H If you want the digitizing oscilloscope to stop when waveform data
exceeds the limits set, toggle Stop After Limit Test Condition Met
(side) to ON.
NOTE
The button labeled Stop After Limit Test Condition Met correĆ
sponds to the Limit Test Condition Met menu item in the Stop
After main menu. You can turn this button on in the Limit Test
Setup menu, but you cannot turn it off. In order to turn it off, press
Stop After and specify one of the other choices in the Stop After
side menu.
Now that you have set up the instrument for limit testing, you must turn
limit testing on in order for any of these actions to take effect.
3. Ensure that Limit Test (side) reads ON. If it reads OFF, press Limit Test
(side) once to toggle it to ON.
When you set Limit Test to ON, the digitizing oscilloscope compares
incoming waveforms against the waveform template stored in reference
memory according to the settings in the Limit Test Sources side menu.
You can compare a single waveform against a single template, more than
one waveform against a single template, or more than one waveform with
each one compared against its own template. How Limit Test operates
depends on which type of these comparisons you choose.
Single Waveform Comparisons
When making a single waveform versus a single template comparison,
consider the following operating characteristics:
H The waveform will be repositioned horizontally to move the first sample
in the waveform record that is outside of template limits to center
screen.
H The position of the waveform template will track that of the waveform.
Single and Multiple
Waveforms